Lubricating means for sewing machine needle-bar mechanisms



AOct. 6, 1936. A. B. cLAYToN LUBRICATING MEANS FOR SEWING MACHINE NEEDLE BAR MECHANISMS Filed June 8, 1935 Patented Oct. 6, 1936 UNITED STATES LUBRICATING MEANS FOR SEWING MA- CHINE NEEDLE-BAR MECHANISMS Andrew B. Clayton, Union, N. J., assigner to The Singer Manufacturing Company, Elizabeth, N. J., a. corporation of New Jersey Application June 8, 1935, Serial No. 25,533

Claims.

This invention relates to sewing machines, more particularly of the typey having a frame including an overhanging bracket-arm and a drive shaft which is journaled in ball-bearings 5 in the overhanging bracket-arm and at one end carries a crank which is connected by a link to the reciprocatory needle-bar of the machine. Diiliculty has been experienced in lubricating the needle-bar driving mechanism of a machine of this type, for the reason that a ball-bearing excludes the possibility of pick-up of lubricant by the main-shaft from its bearing for conduction to the moving bearings of the needle-bar driving mechanism in the manner disclosed for example in U. S. patent to Dial et al.,y No. 772,502, dated Oct. 18, 1904.

It has been proposed, as disclosed in U. S. Patent No. 1,998,588, dated Apr. 23, 1935, to overcome the difficulty in question by providing the main-shaft with an axial bore which is extended from the needle-bar crank-and-link mechanism through the shaft bearing and is connected by a lateral duct leading outwardly of the shaftv to a lubricant-containing sleeve or reservoir surrounding the shaft Within the sewing machine bracket-arm.

With a lubricator, such as disclosed in said U. S. Patent No. 1,998,588, the oil-reservoir is diicult of access for replenishment of the lubricant supply and there is nov means of readilyV ascertaining when replenishment of the lubricant supply is necessary. Further, there isa tendency for a lateral inlet duct to quickly throw all of the oil out of the shaft when the machine is running.

There is another objection to the placing of an oil-reservoir sleeve about the shaft and that is due to the tendency of the packing glands at the ends of the sleeve to warp or spring the shaft, when screwed up sufficiently to be oil-tight, thus unbalancing the shaft and causing an annoying increase in vibration when the machine is operated at high speed.

The present invention aims to provide lubricating means for a sewing machine needle-bar mechanism which will not imbalance the shaft `and which is readily accessible for replenishment of the lubricant supply, the need for which can be seen at a glance. A further object of the invention is to provide means to avoid flooding of the needle-bar mechanism with oil.

With the above and other objects in View, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth. and illustrated in the accompanying drawing of a preferred embodi- (Cl. 11B-256) ment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawing Fig. 1 is a longitudinal vertical section through the bracketarm of a sewing machine embodying the invention. Fig. 2 is a similar view, on an enlarged scale, of the crank-and-link mechanism for driving the needle-bar., Fig. 3 is a section on the line 3 3, Fig. 2. Fig. 4 is a section on the line 4 4, Fig. 2. Fig. 5 is an axial section through the oil reservoir, showing the holding screws for the endcap. Fig. 6 is a face view of the oil reservoir, showing the oil-level when stationary. Fig. 'l is a similar view showing the annular appearance assumed by the oil supply When the machine is running.

In the preferred embodiment of the invention illustrated, I represents the standard of the overhanging bracket-arm 2 of a sewing machine, the arm 2 terminating as usual in the head 3 in which the reciprocatory needle-bar 4 is mounted.

Journaled within and lengthwise of the bracket-arm 2, in the conventional ball-bearings 5, 6 is the main-shaft 'I which is bored out longitudinally from end to end to provide the alined ducts 8, 9, the latter of which is somewhat smaller in diameter than the former which is closed at the end of the shaft by the oil-tight screw-plug I0.

Fixed to the shaft 'I is the crank-head II in which is tightly fixed the hollow crank-pin I2 tted with the internal wick I 3. The crank-pin I2 is closed at its inner end I4 and the Wick I3 receives oil from the shaft bore 8 through the alined lateral ducts I5, I6, I'I in the shaft "I, crank-head Il and crank-pin I2, respectively.

JournaledV on the crank-pin I2 is the bearing boss I8 at the upper end of the link I9 the bearing boss 2.0 at the lower end of which has journaled in it the lateral pin 2| clamped to the needle-bar 4. The upper end boss I8 on the link I9 is closed at its outer end at 22 and the crank-pin I2 has no lateral ducts leading outwardly from the wick I3 to the bearing surface for the iink I9. Hence, all of the oil supplied to such bearing surface must pass endwise through the Wick I3 to the extreme end of the crank-pin I2 and work back along the bearing surface of such crank-pin in which is cut the longitudinal oil-groove 23 stopping short of the free end of the crank-pin. The groove 23A communicates with the circumferential oil-groove 214 in the crank-pin from which oil passes through the duct 25 in the link I9 to the bearing surfaces within the boss 20 at the lower end of the link. No oil can be thrown from the enclosed outer end of the crank-pin I2 and the oil must pass through the entire length of the wick I3 before it reaches the crank-pin bearing surfaces. The Wick I3 is long enough to permit of its being packed sufficiently tight to avoid ooding of the parts with oil. Y

The lateral pin 2| on the needle-bar is also f1tted with'an internal wick 26 and has cut in its bearing surface the longitudinal oil-grove 21 and the circumferential oil-groove 28. The pin 2I is also formed with the radial apertures 2S through which the wick 26 picks up oil from the bearing surfaces between the pin 2I and link I9. The wick 26 lubricates the slide bearing between the slide-block 30 carried by the pin ZI and the slideway 3| in the guide-block 32 secured within the bracket-arm head 3. The crank-head II is formed with an undercut groove 33 within which is disposed the oil sling 34 on the boss I8 at the upper end of the link I9. The head 3 is provided internally at its lower end with the usual oil sump 3.

Screwed into the bore 9 at the opposite end of the shaft 1 is the externally threaded and internally apertured axial neck 35 of the cylindrical oil reservoir 36 the outer end of which is closed oil-tight by means of the glass disk or window 31 which is clamped upon the gasket 38 by means of the cap-ring 39 into which are threaded the holding screws 40. The oil-reservoir 36 is thus carried by the shaft 1 and surrounds the centerline cr axis of the shaft 1 produced beyond the rearward free end of the latter. Such reservoir may be supplied with fluid lubricant through the side opening normally closed by the oil-tight screw-plug 4 I.

The oil-level 42 should be maintained high enough to cover the axial aperture 43 when the machine is at rest, as shown in Fig. 6, so that oil may flow into the shaft apertures 9 and 8. When the machine is running, the oil in the reservo-ir 36 will assume an annular form with a central or axial air bubble 44 exposing the axial aperture 43, as shown in Fig. 7. On account of the small size and axial position of the oil inlet aperture 43, and the absence of a lateral inlet duct rotating with the shaft 1, there is little tendency for the oil to be thrown back from the shaft 1 into the oil-reservoir 36. This tendency is governed by the sizeof the inlet axial aperture 43, being reduced as the size of such aperture is reduced. Oil which has passed through the reduced aperture 43 into the shaft duct 9 and particularly into the still larger duct 8 adjacent the crank head I I will be sufficiently trapped against reverse flow to insure an adequate supply of oil to the crank and link needle-bar driving mechanism at all times. So long as the oil-reservoir 36 is at least half full, oil will enter the shaft 1 through the inlet'duct 43 when the shaft is stationary and regardless of the exact angular position at which the shaft is stopped. The oil level 42 may be checked at a glance through the glass window 31 when the machine is at rest.

The shaft 'I carries the usual balance wheel 45 having the belt-groove 46 for connection to the usual driver. The shaft 1 may also carry the clip-belt pulley 41 which may be connected by the clip-belt 4B to the sewing machine bed-mechanism (not shown). The oil-reservoir 36 also functions as a cap screw to clamp together the hub of the balance wheel 45, the hub of the beltpulley 41, the collar 49 and the inner race ring limitation of the invention to the preferred embodiment thereof shown and described, as modifications may obviously be made in the forms and relative arrangements of parts Within the spirit of the invention which is not limited except .insofar as the appended claims and prior art may require, l Y

Having Ithus set forth the nature of the invention, what I claim herein is:-

1. The combination with a sewing machine bracket-arm terminating at its free end in a head, of a shaft journaled in said bracket-arm, a crank at one end of said shaft within said head, a reciprocatory needle-bar in said head connected to be driven by said crank, the opposite end of said shaft projecting exteriorly of the bracket-arm, said shaft having an oil-duct extending longitudinally thereof from said crank to and through the opposite end of said shaft, and a rotary oilreservoir mounted on said opposite end of said shaft in communication with said oil-duct.

2. The combination with a sewing machine bracket-arm terminating at its free end in a head, of a main-shaft journaled in said bracket-arm, a crank at one end of said shaft within said head, a reciprocatory needle-bar in said head connected to be driven by said crank, the opposite end of said shaft projecting exteriorly of the bracketarm, said shaft having an oil-duct extending longitudinally thereof from said crank to and through the opposite end of said shaft, and a rotary oilreservoirmounted on said opposite end of said shaft and communicating with said oil-duct through an oil-inlet aperture coaxial with said shaft.

3. The combination with a sewing machine bracket-arm terminating at its free end in a head, of a main-shaft journaled in said bracketarm, a crank at one endl of said shaft within said head, a reciprocatory needle-bar in said head connected to be driven by said crank, the opposite end of said shaft projecting exteriorly of the bracket-arm, said shaft having an oil-duct extending longitudinally thereof from said crank to and through the opposite end of said shaft, and a rotary oil-reservoir'mounted on said opposite end of said shaft and communicating with said oil-duct through an oil-inlet aperture coaxial with said shaft, said oil-reservoir having a transparent oil-tight window in its exposed face.

4.. In a sewing machine, a reciprocatory needlebar, a needle-bar actuating shaft, a crank on one end of said shaft connected to drive said needlebar, a ball-bearing surrounding said shaft adjacent said crank, a rotary oil-reservoir carried by said shaft at the extreme opposite end of the latter and surrounding the axis of said shaft, said shaft being formed with a longitudinal oilduct leading from said oil-reserovir through said ball-bearing to said crank.

5. In a sewing machine, a bracket-arm terminating at its free end in a head, a reciprocatory needle-bar journaled in said head, a drive-shaft journaled in said bracket-arm, ra crank-pin carried by said drive-shaft, said drive-shaft and crank-pin having communicating longitudinal oil-ducts for passage of oil from said drive-shaft into said crank-pin, the oil-duct in said crankpin being open at the free end only of the crankpin for egress of oil, a link connected at its lowy er end to said needle-bar and at its upper end journaled on said crank-pin, said link enclosing the open free end of said crank-pin.

6. In a sewing machine, a drive-shaft having a crank head formed with an undercut recess, a crank-pin projecting from said recess and having an oil-duct extending longitudinally thereof, said drive-shaft having a supply oil-duct in communication with the crank-pin oil-duct, a link having a boss at its upper end journaled on said crank-pin, said boss having a closed outer end and at its inner end extending into said undercut recess, and a reciprocatory needle-bar connected to be driven by said link.

'7. In a sewing machine, a drive-shaft having a crank head formed with an undercut recess, a crank-pin projecting from said recess and having an oil-duct extending longitudinally thereof, said drive-shaft having a supply oil-duct in communication with the crank-pin oil-duct, a link having a boss at its upper end journaled on said crank-pin, said boss having a closed outer end and at its inner end extending into said undercut recess, and a reciprocatory needle-bar connected to be driven by said link, said boss having an cil sling within said undercut recess.

8. A sewing machine having a bracket-arm terminating at its free end in a head, a mainshaft journaled in said head, a crank-pin at one end of said main-shaft and a balance-wheel at the opposite end of said main-shaft, a reciprocatory needle-bar connected to be driven by said crank-pin, said crank-pin having an oilduct therein and said shaft having a longitudinal oil-duct in communication with the crank-pin oil-duct at one end of the shaft and extending longitudinally of said shaft to and through the opposite end of the latter, and a rotary oil-reservoir screwed into the shaft oil-duct and tightened against the hub of said balance-wheel.

9. The combination with a sewing machine bracket-arm terminating at its free end in a head, of a shaft journaled in said bracket-arm, a hollow crank at one end of said shaft Within said head, a reciprocatory needle-bar in said head connected to be driven by said crank, said shaft having an oil-duct extending longitudinally thereof and communicating at one end with said hollow crank, said duct having an oil-intake orice remote from said crank, and means to supply oil to said duct through said oil-intake orice, a portion of said duct Within the shaft being of larger diameter than an adjacent portion of said duct nearer said oil-intake orifice.

10. The combination with a sewing machine bracket-arm terminating at its free end in a head, of a main-shaft journaled in said bracketarm, a crank at one end of said shaft Within said head, a reciprocatory needle-bar in said head connected to be driven by said crank, the opposite end of said shaft projecting exteriorly of the bracket-arm, said shaft having an oil-duct extending longitudinally thereof from said crank to and through the opposite end of said shaft, and a rotary oil-reservoir mounted on said opposite end of said shaft and communicating with said oil-duct through an oil-inlet aperture coaxial with said shaft, at least a portion of the oil-duct in said shaft being enlarged relative to said coaxial oil-inlet aperture to trap oil against reverse flow into the oil-reservoir when the machine is running.

ANDREW B. CLAYTON. 

